Controlled Synthesis of Hollow Micro/Meso-Pore Nitrogen-Doped Carbon with Tunable Wall Thickness and Specific Surface Area As Efficient Electrocatalysts for Oxygen Reduction Reaction

Tuesday, 3 October 2017
Prince George's Exhibit Hall D/E (Gaylord National Resort and Convention Center)
R. Wu (Chongqing university), S. Chen, and Z. Wei (Chongqing University)
Here, we demonstrate a rational design and preparation of hollow micro/meso-pore nitrogen-doped carbon (HMNC) catalysts with micro-, meso-, and macroporosity integrated into one structure through high temperature pyrolysis of the precursor containing polydopamine (PDA) coated silica spheres and FeCl3. The TEM and BET analysis results show that the wall thickness and specific surface area of HMNC can be simply controlled by adjusting the Fe content absorbed on PDA. The ORR activities have a strong correlation with the specific surface area and the wall thickness of the HMNC electrocatalysts. The optimized HMNC catalyst with ~5 nm wall thickness and 1703.5 m2 g-1 specific surface areas showed highest ORR performance, which was comparable with Pt/C in both the reaction current and the initial potential in alkaline media. The remarkable ORR activity is ascribed to its unique hollow micro/meso-pore structure, which can provide shortest diffusion channels for oxygen and electrolyte as well as a high specific area and sufficient exposure of inner-pore catalytic sites. This work provides an important guidance to other researcher in designing and fabricating high performance N-doped carbon electrocatalysts for industrial purposes that range from catalysis and sensors to supercapacitors and lithium-ion batteries.